A neutron activation system (NAS) has been developed on the Experimental Advanced Superconducting Tokamak (EAST) for the investigation of time-integrated neutron yield. It is a robust neutron diagnostic with high precision and a wide dynamic range. Some high purity materials with a proper nuclear reaction energy threshold and cross section are tested as neutron detectors in the NAS, and they are delivered to the tokamak device by a pneumatic transfer system. The length of the pneumatic pipeline is about 50 m, and the transfer time ranges from 10 s to 20 s. The decay gamma rays of the activated samples are measured with a high-purity germanium spectrometer, and its detection efficiencies are 6.9% at 336 keV and 1.7% at 1779 keV, respectively. Indium and silicon samples with a reaction threshold of 0.3 MeV and 4.0 MeV, respectively, were successfully implemented in the diagnosis of DD and DT neutron yield in the EAST. The neutron flux of the NAS was compared with the count of the fission chamber in the EAST neutral beam injection experiment, and the DD neutron yield evaluated by the NAS ranges from 1.9 × 1012 n/shot to 5.9 × 1014 n/shot during recent experimental campaign.

中文翻译：

---

EAST上中子活化系统的研制

已经在实验先进超导托卡马克 (EAST) 上开发了一种中子活化系统 (NAS)，用于研究时间积分中子产额。它是一种可靠的中子诊断，具有高精度和宽动态范围。一些具有适当核反应能量阈值和截面的高纯度材料在NAS中作为中子探测器进行测试，并通过气动传输系统将它们输送到托卡马克装置。气动管道长度约50m，传输时间10s～20s。用高纯锗光谱仪测量活化样品的衰变伽马射线，其检测效率在336 keV时分别为6.9%和1779 keV时为1.7%。反应阈值分别为 0.3 MeV 和 4.0 MeV 的铟和硅样品，已成功应用于 EAST 的 DD 和 DT 中子产额诊断。将NAS的中子通量与EAST中性束注入实验中裂变室的数量进行比较，NAS评估的DD中子产额范围从1.9×1012 n/shot到5.9×1014 n/shot在最近的实验中活动。